Ophthalmology Quiz: Corneal Abrasion and Uveitis

Corneal Abrasion

• Topical steroids are contraindicated in cases of viral corneal ulcers because they suppress the immune response, which can lead to a worsening of the infection, thinning of the cornea, and an increased risk of corneal ulceration.
• Herpes simplex causes decreased corneal sensation.
• Bacterial keratitis usually occurs in contact lens wearers after corneal trauma or entry of a foreign body.
• The cardinal signs of bacterial keratitis are diffuse central infiltration of the corneal epithelium and stroma.

Uveitis

• Uveitis involves inflammatory cells in the aqueous humor/anterior chamber.
• Anterior uveitis is usually unilateral.
• Anterior uveitis is treated with topical steroids and cycloplegics.
• Granulomatous uveitis is associated with darkly pigmented keratic precipitates.
• Ciliary injection is seen in chronic iridocyclitis.
• Ciliary flush helps differentiate between iritis and conjunctivitis.

Lens

• The anterior lens epithelium (germinative zone) is responsible for epithelial cell division and gives rise to new lens fibers.
• Ectopia lentis is seen with homocysteinuria.
• Superior lens subluxation can cause monocular diplopia.
• Correction of unilateral aphakia (no lens) with glasses will cause anisocoria (pupils of different sizes).

Cataract

• After cataract surgery, the lens capsule can become opacified due to proliferation and migration of lens epithelial cells, particularly from the equatorial region of the lens.

Retinal Disorders

• Although some of the retina is sacrificed in PRP, it is worth saving the central vision.
• Focal laser therapy is used to peg down retinal tears and help with leaking vessels.
• Metamorphosis is a feature of non-proliferative macular edema.
• First-line treatment for diabetic retinopathy is Anti-VEGF therapy.
• Microaneurysms are the earliest sign of non-proliferative diabetic retinopathy.
• Hard exudate is the accumulation of lipid in the outer plexiform layer.
• Diabetic retinopathy is the most common cause of blindness in KSA.
• Age-related macular degeneration is the most common cause of blindness in the Western world.
• Diabetes is the most common cause of vitreous hemorrhage.
• Check for diabetic retinopathy immediately at diagnosis of type 2 diabetes, and 5 years after diagnosis of type 1 diabetes.
• High myopia is a risk factor for retinal detachment; hyperopia does not contribute.
• Cataract surgery is a risk factor for rhegmatogenous retinal detachment.
• Scleral buckling surgery is the best treatment for rhegmatogenous retinal detachment.
• Rhegmatogenous retinal detachment is managed by closing the retinal defect (scleral buckling, pneumatic retinopexy).
• Retinal detachment is often associated with low IOP as a result of increased outflow by active pumping of fluid through the exposed retinal pigment epithelium.
• Retinal detachment presents with floaters, curtains, and shadows.
• The most common cause of floaters and flashes is posterior vitreous detachment (PVD).
• Vitreous hemorrhage has a sudden onset of symptoms, is usually unilateral and painless, with floaters and visual loss that is typically worse after sleep.
• Vitreous hemorrhage can occur with proliferative diabetic retinopathy, proliferative retinopathy following vascular occlusion and vasculitis, trauma, retinal breaks, and posterior vitreous detachment without retinal breaks.
• Simple retinal detachment does not involve posterior vitreous detachment.
• Posterior vitreous detachment occurs when the vitreous gel pulls away from the retina.
• When PVD occurs, bleeding can occur as the vitreous gel pulls away, causing holes or tears in the retina.
• Swollen optic disc is due to ischemic optic neuropathy.
• Central retinal vein occlusion (CRVO) presents with a "thunderstorm appearance," meaning it involves spots, flame hemorrhages, and tortuous veins.
• CRVO causes gradual vision loss, while central retinal artery occlusion (CRAO) causes sudden vision loss.
• In CRVO, fundoscopy reveals focal retinal hemorrhages instead of a pale white retina, as seen in CRAO.
• Retinopathy of prematurity involves abnormal neovascularization of the retina in preterm infants.
• Hypertensive retinopathy results in AV nicking, flame-shaped hemorrhages, and exudates. Cotton wool spots are the earliest finding.
• Hypertension can cause sudden painless vision loss by occlusion of the central retinal artery or vein.
• The presence of several yellow-white exudates adjacent to the fovea and retinal vessels is characteristic of CMV retinitis. AIDS patients, particularly those with CD4 counts < 50 cells, are at high risk of CMV retinitis.
• Optic disc swelling can occur with papilledema, CRVO, and hypertensive retinopathy.
• Retinitis pigmentosa may be caused by a null mutation in autosomal dominant cases.
• Rod-cone dystrophy is more severe than cone-rod dystrophy.

Visual Field

• The nasal retina perceives light from the temporal visual field. The temporal retina perceives light from the nasal visual field.
• The lower retina perceives light from the upper visual field.
• Marcus Gunn pupil is a pupillary defect that affects the afferent arm of the pupillary response.
• In relative afferent pupillary defect (RAPD), both pupils dilate when light is shone on the affected eye.
• Amblyopia is one of the causes of RAPD.
• Polycoria is multiple pupils.
• O-centered pupils are corectopia.

Tumors of the Eye and Skin

• Papilloma is the most common tumor of the eyelid.
• The retina is the least commonly involved in metastases because of the blood-retinal barrier.
• Rhabdomyosarcoma is the most common orbital (not ocular) malignancy in children.
• Retinoblastoma is the most common intraocular tumor in children. Biopsy of retinoblastoma shows exner-wintersteiner bodies.
• If a child has asymmetrical red reflex, perform a dilated fundoscopic exam.
• Choroidal melanoma is the most common intraocular tumor in adults.
• Lentigo maligna management is surgery with safe margins.
• Malignant melanoma of the eyelid skin can be treated with cryotherapy, but the first-line treatment is excision with wide margins.
• The lower eyelid is the most common location of basal cell carcinoma (BCC).
• Surgery is the primary treatment for squamous cell carcinoma (SCC) of the skin.
• Eye surgery is associated with bullous keratopathy complications.

Orthopedics

• Anterior instability of the shoulder can be diagnosed by the anterior apprehension test. The anterior apprehension test is used to assess for shoulder dislocation.
• The Speed test is used to diagnose long head of the biceps tendinitis.
• Midshaft femur fractures are treated by plate and screw fixation.
• Hemiarthroplasty replaces the fractured femoral head with a prosthetic implant. It is commonly performed in elderly women with displaced or unstable femur neck fractures, while preserving the native acetabulum.
• If there is subluxation, perform a total hip replacement because the acetabular component has degenerated too much.
• If a patient has an open displaced fracture, disinfect, debride, and perform external fixation.
• If a patient has a closed, displaced fracture, perform open reduction internal fixation (ORIF).

Developmental Dysplasia of the Hip (DDH)

• Apparent leg length discrepancy occurs due to issues above the hip joint, such as pelvic obliquity, scoliosis, or muscle contractures, which makes one leg appear shorter than the other.

Knee Injury and Special Tests

• Quadriceps tendon tear causes inability to extend the knee with a low lying patella.
• A popliteal cyst is due to extrusion of synovial fluid from the knee joint into the gastrocnemius or semimembranous bursa through the communication between the joint and the bursa.
• Excessive synovial fluid production (due to osteoarthritis or rheumatoid arthritis) and positive pressure in the knee during extension can cause passage of the fluid into the bursa and gradual enlargement of the cyst.
• Popliteal cysts are often asymptomatic and present as a chronic painless bulge behind the knee.
• The diagnosis is usually apparent on examination with a soft tissue mass in the medial popliteal space that is most noticeable with knee extension and less prominent with flexion.
• Rupture of a popliteal cyst can cause posterior knee and calf pain with tenderness and swelling in the calf resembling deep vein thrombosis (DVT). An arc of ecchymosis is often visible distal to the medial malleolus (crescent sign).
• Ultrasound (US) can rule out DVT and confirm a popliteal cyst.

Foot and Ankle Injury

• Injury to the anterior talofibular ligament causes inability to plantar flex.
• The Thompson test is used to assess for injury to the Achilles tendon.

Test your knowledge on corneal abrasions, uveitis, and lens anatomy in this comprehensive ophthalmology quiz. Explore contraindications for topical steroids, signs of bacterial keratitis, and treatment options for anterior uveitis. Perfect for students and professionals in the medical field!